Hearing instrument

ABSTRACT

A hearing instrument includes a behind-the-ear component and an external component for being placed in the user&#39;s ear canal or in the user&#39;s ear and a connection link between the behind-the-ear component and the external component. The connection link is reversibly pluggable to the behind-the-ear component and/or the in-the-ear-canal component and has a length that is reversibly adjustable. Fixation means is provided for reversibly fixing the adjusted length of the connection link. The in-the-ear-canal component may be connected to the fixation means and detached therefrom when the same is in the ear canal. An in-the-ear-canal component to be placed in a user&#39;s ear canal can have fixation means for fixing it in the ear canal. The fixation means includes an outer shell shaped to fit in the user&#39;s ear canal and a mounting structure for holding the in-the-ear-canal component. The outer shell is preferably resilient, with an elasticity allowing temporal deformation.

FIELD OF THE INVENTION

The invention relates to hearing instruments, in particular hearingaids.

BACKGROUND OF THE INVENTION

State of the art hearing instruments are usually either behind-the-ear(BTE) hearing devices, in-the-ear (ITE) hearing devices, in-the-canal(ITC) hearing devices or completely-in-the-canal (CIC) hearing devices.BTE hearing devices offer, due to the available space and the resultingpossibility to use receivers of larger dimensions, and the opportunityto provide a rather high amplification and to obtain a usuallysatisfying sound quality. The sound transmission from the BTE deviceinto the user's ear canal has to be done by a sound conduction tubewhich modifies the sound impression since the signal transmissioncharacteristic is not homogeneous over the entire frequency range. Someof these modifications are wanted, others are unwanted and, if possible,are eliminated by means of acoustic filters in the sound conductiontube. ITE, ITC and CIC hearing devices, in contrast, have a shortersound conduction tube or none at all. Also, ITC and especially CICdevices are barely visible from the outside and are therefore preferredby many users. However, they have the drawbacks of limited maximumamplification, limited battery lifetime and limited receiver quality,all due to the limited space available. Also the space in the ear canalhas to be used efficiently and the ear canal essentially has to beclosed by the device so as to minimise acoustic feedback due to theproximity of the sound outlet of the receiver and the sound inlet of themicrophone. This plugging of the ear canal may cause undesirableeffects, known as occlusion effect which has an impact on the perceptionof the wearer's own voice and on the wearing comfort.

In order to combine the advantages of BTE devices and of ITC and CICdevices, approaches have been proposed in which a BTE component iscombined with an external component to be placed in the ear canal. Theexternal component comprises the receiver.

In the following, different aspects of the mentioned application areasare considered.

Acoustical Performance

The quality of the acoustic signal transmission path of a hearing aiddepends on four factors: The sensitivity of the acoustic-to-electrictransducer (microphone), the performance of the signal processing unit,the response of the electric-to-acoustic transducer and the acousticcoupling between the electric-to-acoustic transducer output and the eardrum. Electric-to-acoustic transducers (“speakers”) in hearinginstruments are often termed “receivers”, which term is used in thefollowing for electric-to-acoustic transducers in or for hearinginstruments of all kinds.

Microphones typically used in hearing aids have a sensitivity that ismore or less flat within 10 dB in a frequency range between 100 Hz and 6kHz. Variations from flat response occur both intentionally orundesired. At higher frequencies, there is often a rapid sensitivitydeterioration, typically around 10 kHz, depending on the model. Typicalreceivers for hearing aids show frequency response curves with verycharacteristic structures due to the construction of the receiver (size,spout dimensions, etc.). Above 6 kHz typical receivers exhibit asignificant fall off of the response curve.

For high quality sound perception, however, the ideal frequency responsecurve should mimic the natural acoustics of the ear in the range between20 Hz and about 10 kHz, preferably even between 20 Hz and 16 kHz.

The German patent application publication DE 19634984 describes ahearing aid with several receivers integrated in the otoplastic (thecomponent of the hearing aid which is specifically fit to the ear shapeof the wearer and is worn in the ear canal or which at least protrudesinto the ear canal). The multiple receivers are supposed to provide animproved sound quality. This hearing aid, however, has the drawback thata special new receiver technology has to be applied (multilayer foiltechnology) in order to fit the multiple receivers into the ear canal.This receiver technology has not proven to provide sufficient loudnessand sound quality at all relevant frequencies and accordingly has notprevailed on the market.

Current hearing aids, therefore, still use only mainly one receiver forsound production. The acoustical performance is limited by theconstruction and size of the receiver, making it difficult to provide ahigh quality sound over a wide frequency range.

Connection between a hearing aid main component and an external receiver

Hearing devices, especially hearing aids, that comprise an externalreceiver placed outside the device's housing (most often in the earcanal or potentially the concha), have the problem that the connectionlink between the main component (most often the behind-the-earcomponent) and the receiver has to be adapted to the particular eargeometry of the wearer. Some manufacturers offer an external receivercomponent comprising a receiver embedded in a housing, a connection linkmade of flexible, partially pre-shaped and reinforced plastic tubingwith two wires establishing the electrical connection between thereceiver and the behind-the-ear (BTE) component. The mechanical andelectrical interconnection is made by means of a two-pole plug-socketconnector. Often, different lengths of a connection link are provided ina set. Such a set is for example described in WO 2004/025990 or in WO2004/0010181. The disadvantage of such a set-up is that a plurality ofinterconnection links must be provided to fit the ear geometries. Hencethe hearing professional must always have a set of connection links withdifferent lengths in stock.

Other manufacturers offer behind-the-ear hearing aids with an externalreceiver, which, in contrast, come with a non-detachable interconnectionand with one connection link length. The adjustment to the ear geometrycauses the BTE component to change its position behind the earaccordingly.

EP 0158391 teaches a BTE with an external receiver with a connectionlink that is adjustable in length. The adjustment can be done either inthe BTE component or in the receiver component. The basic principle ofthe invention is that the electric connection of the wires to theelectronics in the BTE housing is fixed, i.e. non-detachable, while theconnection link made of a tubular portion can be variably inserted intothe hook or the housing of the BTE component, or into the housing of thereceiver component.

The disadvantage of the solution proposed by EP 0158391 is that theexternal receiver assembly is not easily replaceable since theelectrical conducting wires are attached to the electronics within thehousing in a different way than the connection link. In addition, EP0158391 does not reveal a method for securely attaching the connectionlink to the BTE component. In fact, an actual realisation of such adevice showed severe problems with regard to the mechanical stability.Careless handling of the device caused a significant stress on theconnection link, which may result in wire breaking.

DE 2721469 teaches a method for adjusting the length of the connectionlink by proposing a flexible print with conducting layers on both sides.This flexible print is folded and inserted in a (plastic) tube such toform an inner and an outer conducting layer. This tube can be cut tolength by the hearing professional. The tube is then attached to the BTEcomponent such that, for example, a spike on the BTE component makeselectrical contact to the inner conducting layer and a fastening nutmakes electrical contact to the outer conducting layer and at the sametime provides the mechanical attachment. The mechanical reliability ofsuch a solution is unknown. Also, a faulty length adjustment can not bereversed, since cutting to length is irreversible.

Fixation of a hearing instrument or a component thereof in the ear canal

Comfortable fixation of hearing aids that touch the highly sensitiveskin in the portion of the ear canal beyond the isthmus (i.e. medial tothe isthmus) has always been an issue with deeply fitted hearinginstruments. This is particularly since for this mostly bony section ofthe ear canal physiological factors related to skin thickness andsensitivity are critical issues. Requirements for fitting such hearinginstruments may comprise:

Enable the anchoring of a device safely and comfortably in the bonysection, while minimising the pressure against the skin and avoidingfriction during insertion, i.e. offer a solution which minimizespressure and maximizes retention to prevent the walking out of thedevice (no working itself out)

Allow for atmospheric pressure equalization

Avoid an excessive humidity build-up in the occluded residual volume

Allow to place the device repeatedly at the same position

Avoid infections

Patent literature contains several solutions for fixing a device deeplyin the ear canal. The development of such solutions was mainly driven bycompletely-in-the-canal (CIC) related problems in minimizing acousticfeedback due to the dynamics of the ear canal and/or the wish foravoiding to make ear imprints. Some of the literature describes alsoacoustic seals that are intended specifically for sealing the bonyportion of the ear canal.

Proposed fixation and sealing set-ups comprise:

Soft shells, made of foam or other elastic non porous material (such assilicone)

Soft shells filled with foam

Soft skin layer covering a rigid shell, foam sleeves, silicon rings,etc.

Tips (mushroom like, parachute like, multiple parachutes, ribs, sealrings, jelly or water filled flexible tips and air filled balloons orhearing devices with a mechanically expandable outer fixation structure)

Such set-ups may be custom made or generic. Generic set-ups aresolutions that do not require ear impressions.

Although literature related to deep canal (or peritympanic) devicesdescribes devices that are solely anchored by the seal in the bony part,it is not known how reliable such designs are with regard to unwanteddisplacements or with regard to comfort.

U.S. Pat. No. 5,606,621 discloses a hybrid hearing device with areceiver component separated from the remaining parts of the hearingdevice, where the microphone, the battery and the signal processing unitis in a BTE-like assembly and where the receiver component (in a CIClike assembly) is placed in the ear canal such that it touches the bonyportion of the ear canal. The CIC-like receiver assembly has acustom-made housing which makes contact to the ear canal walls.

US 2004/0047481, US 2004/0047482 and US 2004/0047483 disclose a fixationof the receiver component which is placed in the ear canal and which isconnected through a cable with the remaining parts of a hearing device.This is done either with arms extending from the receiver componenttowards the ear canal walls, or alternatively with a foam disc, in whichthe receiver is placed, and which has a rim that touches the wall of theear canal.

As to mounting outward of the isthmus, patent literature describesessentially two types of mounting schemes for hearing instrumentcomponents in the ear canal.

Universal-fit earpieces containing a hearing instrument component

Custom-shaped earpieces containing a hearing instrument component

U.S. Pat. No. 5,002,151 discloses a universal fit earpiece with auser-disposable sleeve comprising soft polymeric retarded recovery foamthat can be compressed to be freely insertable into a person's ear andallowed to recover to become wedged in the canal. The sleeve isdetachably attached to the ear piece of a hearing aid, which includesany sound transmission device. Preferably, the sleeve is detachablyattached to the ear piece by mating of screw threads on the sleeve andthe ear piece. The ear piece may be a separate component from thehearing aid. The component is made either of rigid or flexible plasticand has connecting portions of various lengths depending on the depth ofinsertion of the sleeve into the canal. The sleeve may be of variouslengths depending on the depth of insertion into the ear canal desired.The sleeve/ear piece assembly may also have a layer of soundtransmitting scrim over its central opening to minimise penetration ofthe connecting portion past the end of the sleeve. A venting system isproposed by means of at least one flute on the exterior surface of thefoam sleeve. Deformation of the tip due to the ear canal dimensions willcause the vent cross sections to change unpredictably, such that theacoustic coupling changes correspondingly.

U.S. Pat. No. 5,887,070 discloses an insert earphone in which a piece offoam material is used to resiliently mount a receiver within a chamberportion of a one-piece plastic housing member. The receiver has anoutput port extending through a central aperture of the piece of foammaterial and into one end of a passage defined by a tubular portion ofthe housing member with a damper being disposed in the other end of thepassage. The tubular portion is inserted into an ear tip or othercoupling device and has an enlarged diameter end section to achieve alocking action. The unitary housing is attached to an ear tip which alsomade of foam to adapt to the ear canal geometry. No venting is providedfor.

U.S. Pat. No. 6,129,174 discloses an acoustic coupler adapted for usewith an intra-canal receiver module which can be deeply inserted intothe ear canal of the user while making minimal contact with the walls ofthe ear canal. The minimal contact feature of the invention allows theacoustic coupler to seal the ear canal acoustically and anchor a hearingdevice at an optimal depth within the ear canal, while maximizing theuser's comfort. The acoustic coupler is manufactured from a soft,pliable elastomer that allows it to conform readily to the shape of theear canal. The acoustic coupler incorporates structural supports thatallow the coupler to maintain an acoustical seal and withstand theinward pressure of the ear canal wall while making minimal contact withthe ear canal. A vent pathway for control of occlusion effects is alsoprovided.

WO 99/07182 discloses several tips which are attached to a universalreceiver housing. None of them is intended to be custom-shaped. Thematerial properties of the acoustic coupler are described as soft andcompliant to adapt to the variable and irregular shape of the human earcanal.

WO 01/69972 discloses a flexible tip for a hearing aid including amushroom shaped tip, an inner portion having a bore and a receivermounted within the bore. The receiver can be housed and sealed within areceiver housing. The receiver housing can include a spring having ahigh compliance along a longitudinal axis and transverse axis, toprovide flexibility in the flexible tip. The spring can also have a highstiffness along a radial direction about the circumference of the springto provide support of the flexible tip from radially directed loads.

U.S. Pat. No. 5,572,594 discloses an ear canal device holder for devicesother than speaker/microphone amplification systems that are to beinserted into the canal of the human ear. The device holder is made of aflexible silicone material comprising a body and structural supportelement(s) such that the device is held within the body of the holderand the body and device are secured in the ear by the structuralelement(s). In addition the device holder minimises the attenuation ofsound waves that pass through the ear canal to the tympanic membrane,while maximising comfort and secure fit.

US 2004/0047483 discloses a unitary receiver housing from that issuspended in the ear canal by means of radially extending structuralelements such as arms or discs. With the use of arms, which are bentinside the ear canal in order to accommodate the individual shape of theear canal, open fitting is therefore optimally supported in terms ofeffective vent size.

WO 2004/100608 and US 2004/0215053 disclose balloon expandable and selfexpandable hearing devices and receiver modules, being further examplesof universal-fit set-ups.

The disadvantage of all universal-fit s receiver or hearing deviceholder solutions is that the positioning of the receiver within the earcanal is not reproducible. In some cases, such as is described in US2004/0047483, the effective vent size is a priori not known since it isdefined by the ear canal geometry which is intentionally not beingdirectly or indirectly measured by taking ear impressions. The resultinguncertainty of positioning and venting causes variations of the acousticcoupling, which limits the acoustic performance of the hearing aid: thehearing aid's gain may not be optimised for the particular geometry theearpiece assumes when inserted in the ear canal. Further, the assemblyis usually not firmly positioned in the ear canal and may walk outand/or may cause a tickling sensation, either during jaw movements orwhen the assembly is touched from the outside with fingers.

CH 664057 discloses hearing aids with custom shaped components. Thesubject is a BTE hearing aid with transducers in separate, sound proofhousings made such that sound can reach the microphone or be radiated bythe receiver only through dedicated openings, i.e. the microphone inletor the receiver outlet. In one embodiment, the receiver housing isplaced within the otoplastic. The otoplastic may have a (conventional)venting.

However, such a set-up with a custom shaped CIC component has thedisadvantage that the volume between the CIC component and the tympanicmembrane is largely closed which reduces the wearing comfort andincreases the occlusion effect. Also, the receiver has to be assembledin special, custom-made set-up. It is not possible to exchange receiversexcept by replacing the entire CIC component.

US 2004/025990 describes an earpiece auditory device including abehind-the-ear (BTE) component, which includes processing circuitry. Inan embodiment, the device also includes a completely-in-canal (CIC)component, shaped to fit into the ear canal of the user such that ittouches the bony portion of the ear canal. In some embodiments, the CICcomponent includes either a universal fit or a custom fit ear mold. Thecustom fit ear mold can be fabricated using a rapid prototypingtechnology, in which the contours of the user's ear canal are scanned,and the scan data is used either directly or indirectly to replicate theear canal contours of that user into the custom fit ear mold. In someembodiments, the ear mold is detachably interconnected with a speakermodule, preferably using either an intermediate sleeve or a detachablelocking pin assembly. In another embodiment, the speaker module ispermanently encapsulated within the ear mold. It is mentioned, that inone embodiment the CIC unit has an open mold configuration or a vent,meaning the ear canal of a user is at least partially open when CIC unitis inserted so deep into user's ear canal as to touch the bony portion.

However, configurations suffer from the drawback that even if theconfiguration is an open mold configuration or has a vent, it is may bedifficult to provide enough air exchange between an inner portion of theear canal and the outside. Also, such state-of-the-art custom shapedearpieces may usually not be made compressible and cause discomfortduring jaw movements.

SUMMARY OF THE INVENTION

It is a first object of the invention to provide a hearing instrument,especially a hearing device, overcoming drawbacks of existing hearinginstruments which especially is suited for providing a high qualitysound perception. Preferably, the hearing instrument should maintain thepossibility to use high quality receivers, which especially in view ofthe sound quality at low frequencies, have to have a certain minimalsize.

According to the first aspect of the invention, a hearing instrumentwith at least one microphone and signal processing means (usuallycomprising an amplification functionality) comprises at least tworeceivers having a different frequency response. At least a first one ofthe receivers is adapted to be placed outside the ear canal, for examplein a behind-the-ear component.

A different frequency response of two receivers may be achieved by avariety of measures, such as different receiver sizes, differentgeometries, different materials, different wirings, different passiveand active electrical components (for example different coils if thereceivers are of an inductive type), different physical principles (forexample an inductive receiver and a capacitive receiver, or an inductivereceiver and a piezoelectric receiver may be used), differentoutcoupling, combinations of these, etc.

Preferably, the signal processing means are configured so as to feedoutput signals of different frequencies to the at least two receivers.For example one receiver may be fed with a first output signal, thefrequency spectrum of which is such that it essentially comprises signalproportions between 0 and a certain splitting frequency, whereas theother receiver is fed with a second output signal with a frequencyspectrum essentially starting at the splitting frequency. In otherwords, the signal processing means as a whole have implemented thefunction of a frequency separating filter.

The hearing instrument preferably also comprises a sound conductionelement, such as a sound conduction tube connecting the first receiverwith the ear canal.

The concept according to the first aspect of the invention features thesubstantial advantage that it makes an improved overall sound qualitypossible. Specific receiver designs may be used, for example onereceiver optimised for high frequency sounds, and another one for lowfrequency sounds. This provides the possibility of enhancing the rangewith a largely flat frequency response. Nevertheless, receivers of theknown kind with the known sizes may be used. Further, the inventionprovides the possibility of reducing the instrument's power consumptionand to reduce unwanted sound modification effects, since receiversand/or sound conducting elements may be operated closer to theirresonance frequencies than if only one receiver covering the wholefrequency range is used.

Besides the fact that at least two receivers are suited to obtain awider frequency response, such a solution may also be advantageous inthe case where negative impacts on the performance of the hearinginstrument due to mechanical vibrations produced by any of the receiverscan be reduced by an adequate design which places the components at themost beneficial locations.

In an especially preferred first embodiment, a second one of thereceivers is placed in the ear canal. In this embodiment, the soundconduction tube may also comprise an electrical connection from theoutside-the-canal (preferably behind-the-ear) component to the secondreceiver. In a first variant of this embodiment, the first receiver (theone outside the ear canal) is used as a receiver for high frequencysounds (a ‘tweeter’), whereas the second receiver serves as a receiverfor low frequencies (a ‘woofer’). However, it is also possible that thefirst receiver (the one outside the ear canal) is operated as a wooferand the second one as a tweeter. This second variant is especiallypreferred in cases where available space is an issue since woofers areusually of larger dimensions than tweeters and hence tweeters can moreeasily be placed in the ear canal. Additionally, thin diameter soundconduction tubes can be used for the transmission of low frequencysounds. In contrast, high frequency sounds would negatively be affectedby smaller diameters due to the acoustic transmission characteristic ofa sound conduction tube. This second variant may consequently also bepreferred in cases where a high amplification at high frequencies isdesired. The second variant may also be preferred where the used soundconduction elements have wanted resonant frequencies at low frequencies.

This first embodiment features the substantial advantage that limitedspace is used in both, the ear canal and the behind-the-ear component.The required size in the behind-the-ear component is especially small ifthe high frequency receiver (the “tweeter”) is located in thebehind-the-ear component.

In another embodiment, both receivers are placed outside the ear canal,for example in the behind-the-ear component. The sound is preferablydelivered through a sound conduction channel or through at least twosound conduction channels to the ear canal. In the case of more than onesound conduction channels, the channels may be mechanically coupled toeach other. They may for example be formed as two bores in a singlesound conduction tube. As an alternative, there may be two separatesound tubes.

In this entire text, “in-the-ear-canal” or “in-the-canal” includes anyarrangement where the elements concerned are at least partially placedin the ear canal of a user, including the classical “in-the-canal” (ITC)and “completely-in-the-canal” (CIC) arrangements. “Outside-the-canal” or“outside-the-ear-canal” subsumes elements that are primarily locatedoutside the ear canal and includes behind-the-ear elements, elementsplaced in the concha or elements at places more remote to the ear canal.An “external” component is a component that is placed outside thehousing of a main component of a hearing instrument, such as a componentplaced outside the BTE component housing. The main component in thisrespect is usually the component that comprises a better part of thesignal processing means (such as a digital signal processor) and abattery compartment.

It is a second object of the invention to provide a hearing device withan external receiver that overcomes drawbacks of prior art hearingdevices with external receivers and that provides mechanical stability,variability and does not require an abundance of parts to be deliveredwith the device.

According to the second aspect of the invention, a hearing instrumentcomprising at least one acoustic-to-electric input converter (amicrophone), a signal processing unit, which preferably includes anamplification functionality and an output converter (a receiver) isprovided. At least the signal processing unit—and preferably also abattery compartment and possibly also the at least one microphone—iscontained in a behind-the-ear component which fits behind a user's ear.The behind-the-ear component may also comprise a detachable ornon-detachable hook. The hearing instrument further comprises anexternal component for being placed in the user's ear canal or in theuser's ear and which comprises at least one receiver, and a connectionlink between the behind-the-ear component and the external component,the connection link comprising at least two electrical contact lines.The connection link is reversibly connectable (for example pluggable) tothe behind-the-ear component and/or the in-the-ear-canal component andhas a length that is reversibly adjustable. The hearing instrument alsocomprises fixation means for reversibly fixing the adjusted length ofthe connection link.

“Reversible” in the context of this text means that a fixation may bereleased destruction free and preferably be re-fit a plurality of times.

Preferably, the external component is an in-the-ear-canal component. Thein-the-ear-canal-component may be free of parts protruding from the earcanal and thus be a completely-in-the-canal component.

Due to the concept of the invention, the in-the-ear-canal component canbe detached from the housing of the behind-the-ear component without theneed to open the behind-the-ear component in a manner that sensitiveelectronics is exposed.

In a first embodiment of the invention, the connection link is formed bya connection element which on one end is pluggable to the externalcomponent and on the other end is fixedly connected with thebehind-the-ear component and is insertable into a cavity of thebehind-the-ear component to varying extents. In the present text, anoptional “hook” is part of the behind-the-ear component. Of course, thementioned cavity may also be present in the hook instead of a main partof the BTE component.

According to an alternative, preferred principle of the second aspect ofthe invention, a connection element for forming the connection link hasone end with at least two electrical contacts which cooperate withcorresponding electrical contacts of the behind-the-ear component or theexternal component so as to form a position variable contact. Positionvariable contacts in this text are contacts between two elements thatcan be brought in contact with each other in a range of relativepositions or in plurality of discrete relative positions. An example ofa position variable contact is a slider contact. However, also otherkinds of position variable contacts may be envisaged. A first example ofsuch on other kind of position variable contacts comprises threadedcontacts, where a threaded shaft and its inside thread counterpart haveat least a first and a second electrically conducting section formingthe first and second electrical contacts and an electrically insulatingsection therebetween. A second example is based on electrical contactsthat have a geometrical structure that allows them to be snapped on eachother in a plurality of possible discrete positions. Such a geometricalstructure may comprise at least one protrusion of one electrical contactco-operating with one of a plurality of corresponding indentations ofthe corresponding electrical contact. This first and second examplefeature the advantage that the contacting functionality may be combinedwith the fixation functionality.

The concept of the position variable contact has several advantages. Forexample, there is no need to deform a terminal proportion of aconnection element in order to vary the length of the connectionelement, as is the case in the first embodiment, where the length of aconnection element proportion in a given cavity is varied with a fixedend. Such deformations, given the dimensions present in a behind-the-earcomponent may cause substantial stress on the connection element and itselectrical leads. In contrast, the concept of the position variablecontacts allows the connection element to be relatively stiff,especially at a terminal portion carrying the electrical contacts. Also,a relatively large range of position variations is possible.Nevertheless, the first and second electrical contacts may be protectedin their entire range by being placed in a cavity of the behind-the-earcomponent (or possibly the external component if the external componentis large enough).

In embodiments of this preferred principle, the length of the connectionlink can be varied by inserting the connection element in thebehind-the-ear component (or possibly the external component) to varyingextents. The connection element can be fixed with regard to itslongitudinal position (i.e. the extent of its introduction in thebehind-the-ear component or the in-the-ear-canal component) and possiblyalso with regards to its angular position by the locking means. Thelocking means may be separate locking means or may, as previouslymentioned, be a functionality of special embodiments of the positionvariable contact. The connection element may be fixedly connected to theother component, i.e. to the external (in-the-ear-canal orin-the-concha) component or the behind-the-ear component, respectively.

In most embodiments, due to the limited space in the in-the-ear-canalcomponent, the position variable contact is formed between theconnection element and the behind-the-ear component, whereas theconnection element is fixedly connected to the in-the-ear-canalcomponent.

A slider contact between first and second electrical contacts may bebased on the following principle: The first electrical contacts have asurface with a certain extension in a longitudinal direction (thelongitudinal direction—except for a possible bending—for examplecorresponding to the insertion direction of the connection element),whereas the second contacts exert a contact force on the firstelectrical contacts so that an electrical contact is made. As analternative, the first contacts—comprising the surface that is extendedin the longitudinal direction—may be spring contacts exerting thecontact force.

Another principle is that the first and second contacts are boththreaded. The at least two different first and second contacts ordifferent polarities, respectively, are arranged with respect to eachother at a distance in the longitudinal direction. Correspondingelectrical contacts of different polarities are in this context forexample contacts for “positive” and “negative” or for “signal” and“neutral”, etc.; more than two “polarities” may be present.

The concept of preferred embodiments with a position variable contactmay also be used in hearing instruments where the external receiver isarranged in a component to be placed in the concha instead of in the earcanal. Also in this case, the slider contact is preferably formedbetween the connection element and the behind-the-ear component, whereasthe connection element is fixedly connected to the in-the-ear component.

Especially preferred embodiments are based on a combination of the firstaspect of the invention with a second aspect of the invention. In thiscase an output of the receiver in the behind-the-ear-component could beacoustically coupled to the cavity in the BTE component, from where thesound couples into the bore of the sound conduction tube, which may beintroduced into the cavity to varying extents. In embodiments where thecavity is present in the hook of the BTE component, the receiver may bemounted in the BTE component in a state-of-the-art manner.

In alternative embodiments, the external component comprises the solereceivers or all of a plurality of receivers of the hearing instruments.

The second aspect of the invention also concerns a method of adapting ahearing instrument, for example in accordance with the second aspect ofthe invention, to a user's atonomy. In this method, the hearinginstrument comprises a behind-the-ear component and an externalcomponent for being placed in the user's ear or in the user's ear canaland which comprises at least one receiver, and a connection link betweenthe behind-the-ear component and the in-the-ear-canal component, theconnection link comprising at least two electrical contact lines, theconnection link being reversibly connectable to the behind-the-earcomponent or the external component. The method comprises the steps ofplacing the behind-the-ear-component behind the user's ear, of placingthe external component in the user's ear canal or the user's ear, ofadjusting the length of the connection link until a comfort fit isachieved, and of applying a locking means to fix the length of theconnection link.

It is a third object of the invention to provide a hearing instrumentwhich comprises a component that is placed in the ear canal and fixationmeans for fixing said component in the ear canal, which fixation meansovercome drawbacks of prior art fixation means and which especiallyprovide a safe, pain free insertion and anchoring in the canal andremoval therefrom. Preferred embodiments should especially be suited foranchoring deep in the ear canal, i.e. between the isthmus and theeardrum.

According to the third aspect of the invention, a hearing instrumentwith a fixation means separate from the in-the-ear-canal component isprovided, which may be positioned in the ear canal and rest therein. Thein-the-ear-canal component may be connected to the fixation means anddetached therefrom when the same is already in the ear canal. This is incontrast to the prior art, where the in-the-ear-canal component has tobe connected to the fixation means—such as an otoplastic or a flexibletip—before its insertion in the ear canal and may only be removed fromthe ear canal together with the fixation means.

In order to achieve this, the fixation means may be designed so that apulling force acting on the in-the-ear-canal component ultimatelyreleases the in-the-ear-canal component from the fixation means but notthe fixation means from the ear canal. In other words, in thisembodiment the retention force against longitudinal displacement betweenthe fixation means and the ear canal is larger than the retention forceagainst longitudinal displacement between the in-the-ear-canal componentand the fixation means.

Whereas insertion of an object in the outer part of the ear canalis—except for the risk to insert it too deeply—relatively uncritical,the insertion of an object such that it protrudes beyond the isthmus isdelicate for the following reasons: Firstly, the isthmus and theassociated bending of the ear canal provides a natural bottle-neck forthe insertion of objects which is delicate to pass. Secondly, as soon asthe isthmus is passed, so is a natural protection of the tympanicmembrane and the middle ear and one has to be very careful not to touchthe tympanic membrane. Thirdly, the skin beyond the isthmus essentiallydirectly covers human bone and is very algesic.

The concept according to the third aspect of the invention allows tohave a hearing professional insert the fixation means and tonevertheless enable the user to insert and remove the in-the-earcomponent without pain and without any danger to damage delicate tissue.The fixation means may remain in the ear canal for several days toseveral months or more, whereas the hearing device component (being forexample a completely-in-the-canal hearing instrument or an externalreceiver component co-operating with a behind-the-ear component) may beinserted and removed frequently.

This concept, therefore, makes possible a separation of the functionsfor fixation (and possibly also acoustic seal) on one hand and forsupplying sound signals to the tympanic membrane on the other hand. Theproposed assembly, therefore, comprises two constituents: a fixationmeans as a first constituent is designed for long-term wear and servesas a kind of ‘scaffold’ to hold the in-the-ear-canal component in place,and the other constituent is the in-the-ear-canal component itself,which can be inserted and removed.

Further, the placement of the in-the-ear-canal component does not dependon deep impressions, i.e. the overall assembly provides a fixation meansthat is independent of the individual ear canal geometry and which holdsthe in-the-ear-canal component in place.

Nevertheless, if the fixation means is not placed deeply in the earcanal, the user himself may be able to place it independently.

The fixation means may be self-expandable and hence adapt to the earcanal geometry. The pressure against the skin may be minimized. Forexample, the fixation means may be formed such that the pressure againstthe skin does not exceed 0.05 N/mm2. The fixation means is formed suchas to hold the in-the-ear-canal component longitudinally, i.e. along theaxis of the ear canal, in place.

According to preferred embodiments, the fixation means comprises aself-expandable tubular element. This element may, according to a firstembodiment, be a hollow, reversibly compressible tube, such as a foamtube, which is made of biocompatible material and has a length of forexample (for grown-up users) between 15 mm and 20 mm. The innercross-section of the tube is at least in a main part smaller than anouter diameter of the in-the-ear-canal component.

According to a second embodiment, the fixation means comprises aself-expanding stent-like tube. Such a tube may have a tube wall with awall diameter that is only a fraction of the ear canal diameter, forexample at most 1/10 or at most 1/20 of the ear canal diameter. The tubewall may have a mesh-like structure and be made of metallic material.The fixation means according to the second embodiment further comprisesholding elements extending from the tube wall inwardly. The holdingelements are elastically deformable by insertion of the in-the-ear-canalcomponent. The holding elements may be hair like and may for example beessentially perpendicular to the tube wall and thus project from thetube wall towards the tube axis.

The second embodiment allows placing an in-the-ear-canal componentdeeply in the ear canal with minimal interference with the physiologicalenvironment. Also, introduction of the fixation means is possible with aminimum of friction between the fixation element and the skin: Thefixation means may be inserted compressed without touching the sensitiveskin. Also, an ear mould does not have to be taken.

In both embodiments, the fixation means may moreover be such that aresistance against longitudinal displacement of the in-the-ear-canalcomponent is larger than the axial pressure exerted on the ear canalskin by the fixation means. In the first embodiment, to this end thetube material may be such that the frictional forces are large (i.e. thecoefficient of static friction between the fixation means and the earcanal wall is for example at least 1) and/or that shear forces encountera comparably higher resistance than compression forces. In the secondembodiment, the holding elements may comprise a non-linearforce-displacement dependence for which an initial displacement, whichis essentially in a longitudinal direction, encounters a higherresistance than displacements in a radial direction. As an alternativeor in addition thereto, the holding elements may comprise barb likestructures which enhance the resistance force against removal of thein-the-ear-canal component and thus for a given desired removalresistance allow to minimise the pressure against the skin The barb likestructures may be supplemented by corresponding structures of thein-the-ear-canal component. As yet another alternative or additionthereto, the holding means at the tube entrance may be stronger, i.e.provide for a larger retention force, than the holding means atpositions where the in-the-ear-canal component is to rest.Stronger—possibly even obstructing—holding means at the tube end mayalso serve as an abutment for the longitudinal displacement of thein-the-ear-canal component. Such an abutment serves to prevent the userfrom introducing the in-the-ear-canal component too deep in the earcanal.

The full assembly in this second embodiment is characterised by aminimum of pressure against the skin and maximum ventilation of theoccluded ear canal. Hence, the risk of fungal or bacterial infections isminimised. The fixation means itself may be made using a minimum ofmaterial so that the inner part of the ear canal including the canalwalls and the tympanic membrane can be visually inspected by the hearingprofessional through the fixation means with the in-the-ear-canalcomponent removed.

The fixation means in accordance with the second embodiment of theinvention is placed beyond the isthmus and the second bend. To this end,a gauge tool may be used to guide the fixation means or parts of it intothe ear canal to the desired location. The fixation means according tothe second embodiment remains in the ear canal for several months untiloutward migration of the skin or other indications necessitate areplacement.

The second embodiment or variants thereof, next to the describedadvantages, is also advantageous from an acoustical point of view. Sincea receiver may be placed beyond the isthmus and preferably as close aspossible to the tympanic membrane, the high frequency response—which isoften critical for hearing impaired persons—may be optimized.

The in-the-ear-canal-component may be any device or device part of ahearing instrument that is meant to be placed in the ear canal of theuser. It may for example be a hearing instrument which as a whole isplaced in the ear canal, i.e. a so-called in-the-canal orcompletely-in-the-canal hearing instrument. It may as an alternative bean external receiver assembly of a hearing instrument which alsocomprises an outside-the-ear-canal component, for example abehind-the-ear component or a component for being placed in the concha.It may particularly be an in-the-ear-canal component of a hearinginstrument according to the first or the second embodiment of theinvention.

In set-ups where the in-the-ear-canal component is part of a hearinginstrument also comprising outside-the-ear-canal-components, the thirdaspect of the invention has the following additional advantages:

Where the in-the-ear-canal component holds a receiver but not amicrophone, a non-occluding fixation of the receiver—such as accordingto the second embodiment of the third aspect of the invention—may becombined with a comparably high amplification. This is because a largespatial separation of the microphone and the receiver precludes feedbackproblems.

For the outside-the-ear-canal component comprising for example themicrophone, a signal processing unit and a battery compartment,conventional constituents as such known from behind-the-ear hearinginstruments may be used. Only the in-the-ear-canal component, which isfor example as small as possible in a non-occluding embodiment, has tobe specifically designed.

The third aspect of the invention also comprises a method of fixing anin-the-ear-canal-component of a hearing instrument to a user' ear canal.Such a method comprises the steps of providing a fixation means adaptedto fit in the user's ear canal and to be fixed therein, of placing saidfixation means in the user's ear canal, and of connecting thein-the-ear-canal component to the fixation means placed in the earcanal. “Connect” does not mean that there has to be a positionally fixedmechanical connection such as a snap-in connection. Rather, “connect”merely defines that the in-the-ear-canal component after being insertedis held in place by the fixation means. The fixation means is insertedin the ear canal without the in-the-ear-canal component by a hearingprofessional or by somebody else, including the user himself. Theconnection of the in-the-ear-canal-component to the fixation means mayfor example routinely be done the user herself or himself.

It is a fourth object of the invention to provide a hearing instrumentwhich comprises a component that is placed in the ear canal and fixationmeans for fixing said component in the ear canal, which fixation meansovercome drawbacks of prior art fixation means and which especiallyprovide a solution letting the ear canal open and has well-definedacoustic coupling characteristics, high comfort and secure fit.Preferred embodiments should especially be suited for in an outerportion of the ear canal, i.e. between the first bend and the isthmus.Further preferred embodiments should ensure a detachable connectionbetween the in-the-ear-canal component and the fixation means.

According to the fourth aspect of the invention, a hearing instrument isprovided which comprises an in-the-ear-canal component to be placed in auser's ear canal and fixation means for fixing it in the ear canal. Thefixation means comprise an outer shell which is shaped to fit (i.e.custom shaped to fit the specific user's ear geometry) in the user's earcanal and a mounting structure for holding the in-the-ear-canalcomponent. The mounting structure is such that the in-the-ear-canalcomponent may have a unitary housing, and that the in-the-ear-canalcomponent is replaceable. The set-up is an open set-up, so that apassage between the ear canal's interior and an outside is maintained.The passage is formed by a clearance between an inner surface of theouter shell and the mounting structure or the in-the-ear-canalcomponent, respectively.

The shell's thickness is preferably not greater than 1 mm, for examplenot greater than 0.8 mm, the cross sectional area of the passage in anorm state (in which for example no external force is applied on theouter shell) is at least 3 mm2, preferably at least 4 mm2. The shell maybe circumferential (i.e. form, in a section along at least one sectionplane, a closed contour) or partially circumferential (i.e. have, insection, an open contour).

The outer shell is preferably resilient, i.e. has an elasticity allowingtemporal deformation.

The mounting structure which may be formed as an inner shell at leastpartially encasing the in-the-ear-canal component. The inner shell mayadjoin the outer shell or may be held, by a support structure, at adistance therefrom, for example centrally within the outer shell.

The mounting structure also may comprise a snap-in locking mechanism forautomatically locking the connection between the in-the-ear-canalcomponent and the mounting structure when the in-the-ear-canal componentis inserted in the ear canal component. The snap-in locking mechanismmay be releasable, in a first variant, by a small tool or a fingernailwhen the in-the-ear-canal component with the fixation means is not inthe ear canal. Alternatively, the locking mechanism may be asnap-in-twist-off mechanism where the in-the-ear-canal component may beremoved by being twisted relative to the fixation means. Apart from thelocking mechanism—which may be provided by a cantilever-like spring—thelocking mechanism does not require any additional tools or parts such asscrews, adhesives, etc.

The size of the passage is preferably large compared to vents ofconventional ITE or CIC hearing instruments. For example, the minimumminimal cross section of said passage may be at least 3 mm2. It may forexample be larger than a third of a cross section of thein-the-ear-canal component (taken in section along a plane perpendicularto a longitudinal axis of the ear canal). Since walls of both the outershell and the inner shell (or other mounting structure) are preferablythin and resilient, the cross sectional area taken by the fixation meansmay be held generally small. Thus, if one manages to provide anin-the-ear-canal component with small dimensions, this advantagetranslates into better venting. This in turn is advantageous because theear is in a condition close to the natural condition.

The fixation means is for example manufactured using the rapidprototyping technology which as such is known for manufacturing shellsof ITE hearing devices or CIC hearing devices.

The fourth aspect of the invention combines advantages of both, theuniversal fit earpiece and custom shaped earpiece approaches. Since theobject that is directly adjacent to the skin is a resilient shell, thefixation means is compressible and comfortable. Nevertheless, the customshaped shell allows a perfect and reliable fit. The risk of walk-out isminimised. Further, in contrast to universal fit earpieces the shape ofthe fixation element when it is introduced in the ear canal is known,and so is the shape of the at least one passage. This makes possiblethat a programming software of the hearing instrument may calculate theacoustic coupling based on the exact geometry of the fixation elementwith the assembled in-the-ear-canal component and determine the settingsof the hearing instrument based on the correct acoustic coupling values(and not just based on some mean value as in the universal fitearpieces). In an initial fitting process, the geometry data may forexample be delivered electronically to the hearing professional, suchthat the programming software may use the data directly, or the geometrydata may be delivered as an abstract code or as specific dimensionalnumbers which may be entered into the programming software by thehearing professional.

A method of fabricating a customised hearing instrument, therefore,comprises the steps of

scanning the user's ear canal, or the user's ear impression

manufacturing a fixation means with an outer shell shaped to fit in theuser's ear canal and with a mounting structure mechanically coupled tothe outer shell and being shaped to hold an in-the-ear-canal componentof the hearing instrument, the fixation means being shaped so as tomaintain a passage from an outside to an interior of the ear canal,

determining, using data obtained from the scanning of the user's earcanal the in-the-ear-canal component position in the ear canal and thedimensions of the passage obtained therefrom,

calculating, using the position and dimensions data, an individualamplification characteristics,

programming a signal processing unit of the hearing instrument so as tohave this amplification characteristics.

Of course, for the calculation of the individual amplificationcharacteristics also further data such as data characterising thehearing loss of the user, are used.

The in-the-ear-canal-component may be any device or device part of ahearing instrument that is meant to be placed in the ear canal of theuser. It may for example be a hearing instrument which as a whole isplaced in the ear canal, i.e. a so-called in-the-canal orcompletely-in-the-canal hearing instrument. It may as an alternative bean external receiver assembly of a hearing instrument which alsocomprises an outside-the-ear-canal component, for example abehind-the-ear component or a component for being placed in the concha.It may particularly be an in-the-ear-canal component of a hearinginstrument according to the first or the second embodiment of theinvention.

Although hearing instruments according to the fourth aspect of theinvention may be used in both, set-ups with an in-the-ear-canalcomponent inserted deeply in the canal (beyond the isthmus) and with anin-the-ear-canal component in an outer portion of the canal, they areespecially advantageous for hearing instruments placed in an outer,cartilaginous portion of the canal.

The term “hearing instrument” or “hearing device”, as understood here,denotes on the one hand hearing aid devices that are therapeutic devicesimproving the hearing ability of individuals, primarily according todiagnostic results. Such hearing aid devices may be Outside-The-Earhearing aid devices or In-The-Ear hearing aid devices. On the otherhand, the term stands for devices which may improve the hearing ofindividuals with normal hearing e.g. in specific acoustical situationsas in a very noisy environment or in concert halls, or which may even beused in context with remote communication or with audio listening, forinstance as provided by headphones. In preferred embodiments of allaspects of the invention, however, the amplification of the activesystem is positive. (The active system comprises the inputtransducer(s), the signal processing means and the outputtransducer(s).) In other words, according to these preferredembodiments, the hearing instrument amplifies the incident sound in atleast a part of the frequency spectrum and thus is suitable for servingas a hearing aid.

The hearing devices as addressed by the present invention are so-calledactive hearing devices which comprise at the input side at least oneacoustical to electrical converter, called a microphone, at the outputside at least one electrical to mechanical converter (receiver), andwhich further comprise a signal processing unit for processing signalsaccording to the output signals of the acoustical to electricalconverter and for generating output signals to the electrical input ofthe electrical to mechanical output converter. In general, the signalprocessing circuit may be an analog, digital or hybrid analog-digitalcircuit, and may be implemented with discrete electronic components,integrated circuits, or a combination of both.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, principles of the invention are explained by means ofa description of preferred embodiments. The description refers todrawings with Figures that are all schematic. The figures show thefollowing:

FIG. 1 a hearing aid system with two receivers.

FIG. 2 a hearing aid system with two receivers and two digital signalprocessing elements.

FIG. 3 a hearing aid system with two receivers and a frequencyseparating filter.

FIG. 4 a further hearing aid system with two receivers.

FIG. 5 a schematic representation of a hearing aid with two receivers,one of which is placed in the ear canal.

FIG. 6 a schematic representation of a hearing aid with two receivers,where both are placed outside the ear canal.

FIG. 7 cross sections of connection elements between anoutside-the-ear-canal (for example behind-the-ear BTE) component and anin-the-canal component.

FIG. 8 a cross section of a further connection element.

FIG. 9 a sketch of an approach of mechanically coupling a soundconduction tube with an electric connection.

FIG. 10 a schematic representation of an assembly of two receivers in asingle housing.

FIG. 11 a schematic representation of an alternative assembly comprisingtwo receivers in a single housing.

FIG. 12 an embodiment of the second aspect of the invention.

FIG. 13 a block diagram of a hearing aid device according to the secondaspect of the invention.

FIG. 14 a schematic representation of the end of a connection element tobe inserted in a BTE component (left: front view, right: side view).

FIG. 15 a cross section of a cavity within the BTE component forreceiving the end of a connection element.

FIG. 16 a cross section of a duct of a BTE component with a sealingO-ring.

FIG. 17 a set screw placed in the BTE component housing or a (mini)hook.

FIG. 18 a contact support part of a connection element with a curvatureof constant radius.

FIG. 19 a sliding contact assembly.

FIG. 20 a variant of a contact support part of a connection element.

FIG. 21 a BTE component cavity for co-operating with the connectionelement of FIG. 20.

FIG. 22 a schematic representation of a connection element comprisingstructures for an interlocking mechanism.

FIG. 23 a counterpart for the connection element of FIG. 22.

FIG. 24 a view of an interlocking set-up of a BTE component and aconnection link.

FIG. 25 a schematic representation of a contact support part of aconnection element with slider contacts and a threaded sleeve.

FIG. 26 a contact support part of a connection element with threadedcontacts inserted in a corresponding threaded counterpart.

FIG. 27 a contact support part of a connection element with contactsthat comprise a structure that form an interlocking mechanism, togetherwith corresponding parts of the BTE component.

FIG. 28 a set-up according to the third aspect of the invention.

FIG. 29 a first embodiment of the third aspect of the invention in aschematic side view.

FIG. 30 a second embodiment of the third aspect of the invention in sideview (left panel) and front view (seen from the tympanic membrane).

FIG. 31 a variant of the second embodiment of the third aspect of theinvention including stopping means and enforced longitudinal fixation.

FIG. 32 an idealised force-versus-deflection diagram of a variant of aholding element.

FIG. 33 very schematically a variant of holding a holding element for afixation means according to the second embodiment.

FIG. 34 a holding element as in FIG. 32 additionally comprising a barbmeans.

FIG. 35 a picture of a self-expandable stent for serving as tubularelement for a fixation means according to the second embodiment of thethird aspect of the invention.

FIG. 36 a detail of a mesh structure of the stent of FIG. 35.

FIG. 37 an alternative variant of the second embodiment of the thirdaspect of the invention.

FIG. 38 an illustration of a typical dependence of the acoustic responseon the longitudinal position of a earpiece in an ear canal.

FIG. 39 an illustration of a typical dependence of the acoustic responseon the diameter of a vent in an earpiece.

FIG. 40 a set-up according to the fourth aspect of the invention.

FIG. 41 a front view, side view and top view (all in section) of afixation means of a hearing instrument according to the fourthembodiment of the invention.

FIG. 42 an illustration of a possible wall structure for the outershell.

FIG. 43 in illustration of alternative embodiments of the fixationmeans.

FIG. 44 in illustration of another alternative embodiment of thefixation means.

FIG. 45 an illustration of yet another alternative embodiment of thefixation means.

FIG. 46 an illustration of a snap on/twist off mechanism for fasteningand detaching an in-the-ear-canal component in the inner shell of thefixation means.

Same reference numerals in different figures refer to same or analogouselements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-3 show examples of hearing aid systems with more than one outputelectric-to-acoustic converter 5.1, 5.2, which converters in thefollowing are named ‘receivers’. The two receivers 5.1, 5.2 in thehearing aid systems shown in FIGS. 1-3 differ from each other in thatthey have different frequency responses. For example, the first receivermay have smaller dimensions and provide an optimal response to highfrequency signals, such as to signals above a particular frequencydepending on the application. This frequency may be 500 Hz, 1000 Hz,2000 Hz, another value between 500 Hz and 2000 Hz or a lower or highervalue. The second receiver may be larger and be optimized for signals oflower frequencies, such as signals below the particular frequency.

The shown examples may be implemented according to the first aspect ofthe invention, potentially in combination with the second aspect and/orone of the third and of the fourth aspect of the invention.

A hearing aid system with a single microphone and two receivers isschematically illustrated in FIG. 1. The system comprises, in asequence, a input acoustic-to-electric converter (microphone) 1,producing an input signal Si, a signal processing unit (SPU) 3,transforming the input signal into two output signals, namely a firstoutput signal So,h, with predominating high frequency signalproportions, and a second output signal So,l with predominant lowfrequency signal proportions, and the receivers 5.1, 5.2. The signalprocessing unit may implement the function of an analog-to-digitalconverter and an digital signal processing stage. It may, depending onthe requirements of the receivers, further comprise one or moredigital-to-analog transforming stage(s). Such a digital-to-analogtransforming stage, however, is not always required, since hearing aidreceivers in digital hearing instruments are often driven by a pulsewidth modulated (PWM) or a pulse code modulated (PCM) digital signalinstead of an analog signal.

Elements of the signal processing unit SPU may be implemented in asingle signal processor or may comprise a plurality of physicallyseparate, appropriately connected elements.

The signal processing unit in all embodiments of the first aspect of theinvention preferably includes an amplification functionality. This meansthat the amplification of the signal processing unit is positive. Inother words, the signal strength of the added analog signals fed to thereceivers is larger than the signal strength of the analog input signalproduced by the input converter(s). However, the first aspect of theinvention is also suitable for hearing instruments which do not requirea positive amplification, such as active hearing protection devices, forwhich the signal processing unit provides a negative amplification(damping).

The digital signal processing stage 3 separates high frequency and lowfrequency components of the input signal according to thecharacteristics of the two receivers 5.1, 5.2. Splitting of a signalinto high and low frequency signals on a signal processor level as suchis known in the art and has been developed and used for audio systems.An example of according audio signal management methods can be found inU.S. Pat. No. 6,349,285, which is incorporated herein by reference.

In the shown embodiments, the hearing aid comprises a single microphone.However, there could also be several microphones and/or other inputdevices—such as a telecoil—, together with according analog-to-digitalconverting means. For example, dual microphone hearing aids are knownwhich may include a beamforming functionality.

Also, although in all described embodiments the hearing aid has tworeceivers, more than two receivers may in fact be used in a hearing aid,for example each receiver for a certain frequency range, or a singlereceiver for low frequency sounds in combination with a multitude ofhigh frequency receivers, etc.

The embodiment of FIG. 2 differs from the embodiment of FIG. 1 in thatit comprises two signal processing stages 3.1, 3.1, one for the highfrequency channel (i.e. for providing an input signal for the firstreceiver 5.1), the other one for the low frequency channel. A controlelement 6 provides a synchronized input for both digital signalprocessing stages. The control element may for example either simplysplit the signal into two (equal) outputs which are fed into the signalprocessing unit which then overtakes the task of digitally filtering anprocessing the filtered signal. (In this embodiment, the control elementmay merely be considered to be a branching of a wiring). Or, the controlelement itself may comprise a filter element which could preferably beanalog if the (for example conventional) SPUs already have a A/Dconverter implemented. Alternatively, the control element may comprise adigital filter if the SPU possesses a digital input. In this case, ananalog-to-digital converter (not shown) will be interposed between themicrophone 1 and the control element 6.

The principle advantage of having to use more than one SPU is that SPUsof conventional single receiver hearing aids may be used. To this end,merely the amplification characteristics of the digital signalprocessing stages has to be set differently: whereas the first signalprocessing stage 3.1 amplifies high frequency sounds and attenuates lowfrequency sounds, the second signal processing stage has an oppositecharacteristics.

Yet another embodiment is depicted in FIG. 3. This embodiment differsfrom the embodiment of FIG. 1 in that the digital signal processingstage only comprises a single output for output signal SO. The digitalsignal processing stage may therefore be a processing stage as suchknown from conventional hearing aids. Frequency splitting is attained,for example, by an analog frequency-separating filter 7 arrangeddownstream of the—single—digital-to-analog converter 4. The two outputsof the frequency-separating filter are fed to the two receivers 5.1,5.2.

As yet another alternative (not shown in the figures) the signalprocessing unit may produce only one signal which signal is fed to bothreceivers. This alternative is suitable for receivers thecharacteristics of which is that sounds of low or high frequencies,respectively, are practically suppressed, so that the receiversthemselves serve as high pass and low pass filters, respectively.

In FIG. 4, an embodiment is shown where no filter is used at all. Inthat case the single output of the SPU 3 (with digital or analogsignals) is fed into the two receivers 5.1, 5.2 which have by designdifferent response characteristics such one receiver predominantlyoutputs sound at low frequencies and the other outputs sound at highfrequencies.

Embodiments of the first aspect of the invention are illustrated inFIGS. 5 and 6. There, dotted lines separate anoutside-the-canal-(preferably behind-the-ear)-component 11, anintermediate signal transmission region 12 and an in-the ear (namely inthe canal) region 13. The reference numerals 1, 3, 5.1, and 5.2 denotethe microphone , the signal processing unit (comprising digital signalprocessing stage together with the analog-to-digital converters, thedigital-to-analog converters and potential other digital or analogsignal processing means arranged between the input converter(s) and thereceivers), and the first and second receiver, respectively.

The first, especially preferred embodiment of the first aspect of theinvention is shown in FIG. 5. The first receiver 5.1 is arranged in theoutside-the-canal component 11, whereas the second receiver 5.2 isplaced in the ear. The signal transmission between the outside-the-canalcomponent and the in-the-canal component is provided by an (airborne)sound transmission channel 15 from the first receiver 5.1 to the earcanal, and by an electric signal transmission channel 16 from the signalprocessing unit 14 to the second receiver, respectively.

According to the embodiment of FIG. 6, both receivers are placed in theoutside-the-canal component. Two sound transmission channels 17 leadfrom the receivers 5.1, 5.2 to the ear canal.

The two channels in the embodiment of FIG. 6 need not be physicallyseparated as is illustrated in panel A of FIG. 7. FIG. 7 shows crosssections of different connection elements between an out-of-the-canal(for example in-the-ear) component and an in-the-canal component of thehearing aid. The connection element of panel A is a sound conductiontube 31 comprising only one bore 32 which is connected, on one side withthe outputs of both receivers and on the other side ends in the earcanal. The sound conduction tube 31, thus carries both channels.

Also the connection element of panel C is suited for the embodiment withboth receivers placed outside the ear canal. The sound conduction tube36 comprises two bores 37, 38 serving as sound conduction bores for theoutput of the first, and the second receiver, respectively. The boresneed not have the same dimensions as in the figure but may rather beadapted so that their resonance frequencies are adapted to the frequencyof the signals they conduct. For example, each bore may containdedicated conventional passive acoustic filters.

The two bores of the sound conduction tube 40 of panel D, in contrasthave different purposes. Whereas the first bore 41 is a sound conductionbore, the second bore 42 contains an electrical wire pair 43 forelectrically contacting a receiver placed in the ear canal. The receiverin the ear canal may be placed in a otoplastic which itself has a soundconduction bore that passes the receiver such that the sound outlet ofthe in-the ear canal receiver is next to the sound outlet from the soundconduction bore, which is coupled to the sound conduction tube andeventually to the receiver in the BTE component. Both sound outletspoint inwards to the eardrum.

The sound conduction tube of panel D, therefore, is suited for theembodiment with one receiver placed in the canal, and another one placedoutside the canal. In contrast to the shown embodiments, the electricalwire pair could also be placed inside a (single) sound conduction bore.

Panels B and E both show cross sections of connection elementscomprising a tube 33; 45 with two electrical wire pairs 34.1, 34.2;46.1, 46.2 for electrically contacting two receivers placed in the ear.In panel B, both wire pairs are placed in a single bore 35, whereas inpanel E the tube contains two bores 47, 48 each comprising a wire pair.Other set-ups, for example with wires encapsulated in tube material maybe envisaged. Configurations with more than one receiver in the canalare described further below.

The sound conduction element of FIG. 8 is made up of two soundconduction tubes 51, 52 mechanically coupled to each other. The tubeshave different sizes and may also have different wall thicknesses and/orbe made of different materials having different elasticities. The tube51 with the larger diameter is preferably used for conducting the lowfrequency sound signals.

In the embodiment of FIG. 9 the electrical wires 72 are also coupled tothe sound conduction tube 71 in an essentially straight manner. Otherways of coupling the wires to a sound conduction tube may be envisaged.

The above described embodiment of combined sound conduction andelectrical signal conduction elements may be coupled to theoutside-the-ear (for example behind-the-ear-) component by means of asnap-on mechanism (electrical contacts may be arranged on the inside orthe outside of a tube surface), by means of a nipple, using a fasteningnut or similar.

Whereas a mechanical coupling of potentially required wires to soundconduction tubes is advantageous, it is not necessary. Embodiments whereelectrical wires are guided independently of the sound conductiontube(s) may be envisaged, too.

FIGS. 6-9 relate to the example of two receivers, but the concepts ofthe shown embodiments may readily be extended to more than two, forexample by coupling the outputs of more than one (or more than two)receivers to one sound conducting bores, by providing more bores thanshown in the figure, by providing more electrically conducting wiresthan shown, etc.

FIGS. 10 and 11 show—in a very schematical manner—concepts of acombination of two receivers in a single housing. Such concepts may beuseful for embodiments of the first aspect of the invention comprisingmore than two receivers, two of which are placed in the ear canal. Theymay also be used in situations where two receivers are placed outsidethe ear canal—for example behind the ear or in the concha—and where itis important to save space. They may, as yet another alternative, beused in hearing aids deviating from the first aspect of the invention,where all of at least two receivers are placed in the ear canal.

A two-receiver device of the kind described in FIG. 10 comprises thefollowing features:

A housing 71 comprising a diaphragm 72, which may, actuated by anelectromagnetic inductive or capacitive drive mechanism, be caused tovibrate and thus generate a first contribution to a sound output.

A piezoelectric element 73 or a MEMS (Micro-Electro-Mechanical System)element placed within the housing and being operable to vibrate excitedby an electrical signal and thus to generate a second contribution to asound output.

The embodiment of FIG. 10 is, in other words, characterised in that alow frequency sound producing element (such as the diaphragm) and a highfrequency sound producing element (such as a piezoelectric element) areboth in the same housing such that their sound producing surfaces areadjacent a common gas filled free volume within the housing.

In the shown, preferred embodiment, the piezoelectric element 73 ismechanically coupled to the diaphragm 72. More concretely, it is placedon the diaphragm. It is caused to vibrate if an according electricalvoltage signal is applied to the high frequency signal contacts 74. Thediaphragm's drive mechanism includes for example conventional excitingmeans 75 such as a coil co-operating with a permanent magnet placed on atuning fork like armature and means—such as a drive rod—for transferringvibrations from the armature to the diaphragm. The low frequency signalcontacts are denoted by 76 in the figure.

The diaphragm and the piezoelectric element placed thereon both excitesound waves 78 in the gas (typically air) in the free volume 77 of thehousing. The sound waves are guided through the opening 79, possibly toa sound conducting tube coupled to it.

The device of FIG. 10 may be varied in that the piezoelectric elementneed not be coupled to the diaphragm but may be coupled to the housingand be placed somewhere else adjacent the free volume 77 of the housing(which free volume, of course, may be shaped differently from the shownembodiment).

The device of FIG. 10 may be used both, as a double receiver placed inthe ear canal or as a double receiver placed in an element outside theear canal to which a sound conduction tube is coupled.

The two-receiver device of FIG. 11 is also suitable for being placed inthe ear canal or outside the ear canal, but it is a preferred embodimentfor applications where it is place in the canal. It comprises:

A housing 81 with a sound producing element placed therein. The soundproducing element is suited for producing high frequency sounds and maybe a diaphragm 82 with a corresponding inductive or capacitive firstdrive mechanism 83 or may be a piezoelectric element.

A second capacitive or inductive drive mechanism 84 operable to cause apart of the housing to vibrate.

The part of the housing that may vibrate may be a flexible membrane 85which forms a part of the housing. In the shown embodiment, the flexiblemembrane forms an end face of the housing. The end face, if the deviceis placed in the canal, faces inward, i.e. towards the eardrum.Alternatively, this part may be an outer shell, a combination of anouter shell and an end face, or even the entire housing.

In the shown embodiment, the membrane 85 comprises a membrane openingfor the high frequency sounds caused by the high frequency soundproducing element.

In FIG. 12, an embodiment of the second aspect of the invention is veryschematically drawn. The hearing instrument shown in FIG. 12 comprises abehind-the-ear component 101 and an in-the-ear-canal component 102. Thebehind-the-ear component comprises sound acquiring and processing means103 and a cavity 104 formed in a hook 106 of the behind-the-earcomponent. The sound acquiring and processing means 103 are connectedwith the in-the-ear-canal component 102 by means of a pluggableconnection link 105. The connection link is implemented by means of aconnection element, namely a cable 110 comprising two wires and a plugconnector pluggable into a corresponding connector of thein-the-ear-canal component 102. In the figure, very schematically a maleplug 111 of the connection element is shown which co-operates with acorresponding female socket 112 of the in-the-ear-canal component 102;however any reversibly pluggable connector could be used. Often, aconnector will comprise guiding means for supporting a smooth pluggingoperation.

The connection link is adjustable in its length in that the connectionelement may be inserted in the cavity through an orifice 117 to avariable extent, as indicated by the arrow 116. Sealing means 118allowing a smooth sliding of the cable with respect to the orifice arealso shown in the figure. In contrast to the shown configuration, thecable in the sliding operation may be guided by a tube instead of justan orifice. It may in yet another configuration by inserted in an innertube which is slidable inside an outer tube.

In practice, the behind-the-ear component will often comprise aso-called ‘hook’, which is a dimensionally stable element hooking thebehind-the-ear component behind the ear and guiding the connectionelement towards an interior of the user's concha. In such embodimentsthe cavity will often be in a transition region between the hook and thesound acquiring and processing means.

The in-the-ear-canal component is arranged in fixation means (not shown)holding it in its place in the ear canal. Such fixation means may be anotoplastic or a self-adjusting fixation means as such known in the art.It may also be a newly developed fixation means, such as a fixationmeans according to the third or fourth aspect of the invention asdescribed further below.

FIG. 13 illustrates a hearing aid system that may be implementedaccording to the second aspect of the invention. The sound acquiring andprocessing means comprise a microphone 1 (usually comprisingpre-amplifier means), the signal processing unit 3 arranged in thebehind-the-ear component 101. The receiver 5, however, is placedexternal component 102, which is for example anin-the-ear-canal-component.

The behind-the-ear component 102 for example also comprises acompartment for a battery (not shown) for the active elements of thesound acquiring and processing means. The external component ispreferably free of any battery means and is only fed by the signaltransmission line formed by the connection link.

The signal transmission between the BTE component and the ITE (includingITC or CIC) component could also be wireless. In that case, the ITE(ITC, CIC) component would require also a battery and the signalprocessing unit to receive the signal and the drive the receiver.

Of course, as an alternative to the system illustrated in FIG. 13, asystem according to the first aspect and comprising at least onereceiver to be placed in the ear canal or another set-up including asignal transmission line between a behind-the-ear component and anin-the-ear-canal component may be used.

In the following, preferred embodiments of the second aspect of theinvention are described, which follow the principle that a positionvariable contact is formed between the connection element and one of thetwo components to be connected, preferably between the connectionelement and the behind-the-ear component.

In a preferred embodiment, the connection element 131 is made in a mainpart of a flexible material such as PEBAX and contains two wiresconnected to the receiver placed in the external component at one end.The opposite end, shown in FIG. 14, is the end which is going to beinserted into the behind-the-ear component. It has a contact supportpart 132, which is made of an insulating material that is preferentiallymore rigid than the flexible material of the connection link main part.The left panel of FIG. 14 shows a front view of the connection elementfrom the contact support part side. A tip 133 of the contact supportpart is tapered such as to facilitate the insertion into the duct of theBehind-the-ear (BTE) component. Two electrical contacts 134 are mountedon the contact support part 132 such to enable electrical contact inopposite radial directions of the contact support part. The contacts arein electrical contact with the wires that are connected to the receiver.The electrical contacts 134 are preferentially rigid and do not producea contact force in radial direction. The contacts are arranged toprovide left-right symmetry, meaning that one pole is on the top and theother pole on the bottom of the contact supporting part, or one pole ison the left and the other on the right. This allows either inserting aconnection link for a left ear or for a right ear. (For the purpose ofthe description of this and the following embodiments it is assumed thatthe receiver is operated in a symmetric mode, i.e. plus and minus polesare labelled simply for easy distinction of the two poles. Of course,the concepts described herein are also suited for non-symmetric modes).

In this preferred embodiment, the BTE component housing has a cavity 141with an inner cross sectional dimension large enough to hold the contactsupport part and partially also the connection link (see FIG. 15). Thelength of the cavity is at such as to allow moving the connection link(with the contact support part) by a sufficiently large amount requiredby fitting the BTE component with the external receiver to the eargeometry of a user. The cavity has two spring electrical contacts 142which, when the connection link is inserted into the BTE componenthousing, are making contact with the electrical contacts on the contactsupport part of the connection link and which are producing asufficiently large contact force to provide a reliable electricalconnection. Preferably, the contact force is also large enough toprovisionally fix the relative position of the connection element andthe behind-the-ear component to enable the hearing professional toverify the physical fitting of the hearing device without the need offixing the position by means of the locking mechanism. To protect theinside of the behind-the-ear component housing from moisture, theorifice or duct 145 of the BTE component housing in which the connectionlink is inserted may be equipped with a sealing means such as an O-ring145 (see FIG. 16).

In this preferred embodiment, the fixation of the connection link withinthe BTE component housing requires a separate fixation means. Onepossibility is to provide a (metallic) set screw 147 with a conical end147.1 which penetrates into the softer flexible material of theconnection link 131 such as to fix the connection link in longitudinaland angular direction (see FIG. 17). A set screw is for example arrangedin the duct of the behind-the-ear component, thus for example on theleft of the O-ring in FIG. 16 or in the hook. Other fixation means canbe applied alternatively; one example is clamping with a fastening nut.

In an alternative embodiment, the contact support part 132′ has adefined curvature with constant radius in its longitudinal direction(see FIG. 18). In this way, the cavity within the BTE component and alsothe duct of the BTE component into which the connection link isinserted, also has a defined curvature with constant radius,approximating the anatomical shape behind the ear just at the locationwhere the BTE component is usually suspended. By doing so, the size ofthe BTE component can be minimized.

In a further alternative embodiment, the contact support part has across-sectional shape which deviates from cylindrical symmetry and thusdefines the angular position of the connection support part and thewhole connection element with respect to the BTE component housing. Anexample of such an assembly is shown in FIG. 19. FIG. 19 shows an endportion 161 of a BTE component with an inserted contact support part 152of a connection element 151. In the shown embodiment, the contactsupport part 152 is essentially plate shaped and for example similar toa flexible print with contacts 154 on the top and the bottom. Thecorresponding contacts 162 belonging to the BTE component in the drawnembodiment are mounted within a sleeve 163 that is inserted into theduct of the BTE component housing. Also shown in the drawing is a(conventional) hook mounting structure 164 with several nipples. Afeature of this kind could also be used as thread to co-operate with afasting nut in embodiments of the invention.

A further embodiment of the second aspect of the invention and includinga slider contact is shown in FIGS. 20 and 21. FIG. 20 shows an endportion of the connection element 171 including the contact support part172 in front view (right panel) and in side view (left panel). Theelectrical contacts 174 fixed on the contact support have the shape of aresilient slab or wire and part are made of highly resilient materialsuch as copper beryllium and are formed such that they are squeezedradially when then the connection link is inserted into the BTEcomponent housing. Within the cavity 181 of the BTE component housing,rigid contact pads 182 as shown in FIG. 21 are mounted which establishthe electrical connection over the longitudinal range required by theapplication.

As alternatives to the fixation described referring to FIG. 17, othertypes of fixation means may be used. In an alternative embodiment theBTE component housing can partially be opened by removing a cover. Bydoing so, the cavity which eventually holds the connection link with theelectrical contacts is accessible. Within the cavity, the two contactpads are mounted. Preferably, the cavity is separated from the remaininginner portions of the BTE component housing by walls, so that theelectronics is well protected during manipulation and length adjustmentin the cavity. The contacts are fed through the walls of that cavity andare connected to the electronics with the remaining inner portion of theBTE component housing.

An example of such an alternative fixation is shown in FIGS. 22-24. Inthis alternative embodiment, the connection element 191 is equipped witha radially extending interlocking structure 192 near the electricalcontacts. An example of such a (in the drawing: male) interlockingstructure is shown in, which depicts a contact support portion 132 of afurther connection element. As shown in FIG. 23, the cavity 197 of theBTE component housing holding the connection link has a given number ofmatching (in the drawing: female) interlocking structures 193,longitudinally spaced apart such as to offer the possibility to chosefrom a number of different lengths between the BTE component and thereceiver component. The hearing professional will then place theconnection link into the cavity at the desired position and will thenclose the cavity by moving a cavity locking element with respect to therest of the BTE component housing. In the shown embodiment, the matchinginterlocking structures 193 of the BTE component housing are formed in alocking element 194 which is movable—for example pivotable—with respectto a fixed part 195 of the housing and which is lockable by closing thecover (not shown in FIG. 23).

FIG. 24 shows a conceptual view of a BTE component, where such analternative fixation is realised by providing the (female) interlockingstructure as described above directly in the cover 202. The cavity 203in this embodiment extends over a long proportion of a rear of the BTEcomponent and is separated from the rest by for example moisture proofcavity walls. The embodiment of FIG. 24 also shows electric contacts 204formed somewhat differently from the previously described embodiments.The electric contacts 204 have a tentacle-like shape and are, like theembodiment of FIG. 20, pre-stressed to press against correspondingelectrical contacts 205 of the BTE component housing. The flexible partof the connection element 206 is denoted by 207 in the figure.

Other interlocking means are possible, on of them is a bolt which isinserted into the BTE component to fix the connection link position. Thebolt locks the interlocking means on the connection link.

A different embodiment foresees the length adjustment by means of athread mechanism (see FIG. 25). The contact support part 212 of theconnection element 211 is cylindrical and has two sections inlongitudinal direction where the cylindrical electric contacts 214 aremounted. In addition, a sleeve 215 with a thread is put over theconnection link at an adequate and fixed position along the connectionlink. The BTE component housing (not shown) has again a cavity withspring contacts that make contact with the cylindrical contact on theinserted connection link. The two electrical spring contacts ofdifferent polarity are, in contrast to the embodiment of FIG. 25,arranged at a distance in axial direction to each other. Thus, theconnection link can freely by positioned in angular direction and can belongitudinally positioned within a range given by the size of thecylindrical contacts, defined such to cover the desired variation of theadjustment-length. The BTE component further comprises a counterpart ofthe threaded sleeve. The sleeve and the BTE component counterpart may bemade of different materials. The thread lead may be defined such thatone full turn corresponds to for example 2 mm so that that lengthadjustment is done quickly. However, it is a disadvantage of such asolution, that the device has to be removed from the user's ear when alength adjustment has to be done. In contrast, the advantage is that thethreads provide the longitudinal fixing and mechanical stability.

The connection link may have position markers on its outer surface thatare visible and help the hearing professional to preset the length ofthe connection link or to control the physical fitting process.

Referring to FIGS. 26 and 27, position variable contacts are describedwhich are not slider contacts. In FIG. 26, the electrical contacts 224of the connection element 221 (the first contacts) and the contacts 225associated with the BTE component housing 226 (the second contacts) areboth threaded. The two first contacts 224 for different polarity and thetwo second contacts each are arranged at a longitudinal distance fromeach other. In the spaces between the contacts of different polarityboth, the threaded portions of the connection element and of the BTEcomponent housing are electrically insulating. The first contacts and/orthe second contacts are extended in longitudinal direction (in the shownconfiguration the first contacts only), so that an electrical contact isformed over a longitudinal range of different relative positions of theconnection element 221 with respect to the BTE component housing. Thesolution of these figures could also be used for the in-the-ear-canalcomponent to adjust the insertion depth.

The connection element 231 of FIG. 27 comprises a radially extendinginterlocking structure as previously described. In contrast to theembodiments described so far, however, the interlocking structure alsocarries electrical contacts 234 co-operating with corresponding contacts235 of the matching interlocking structure of the BTE component housing233.

Combinations or variations of the set-ups of the above embodiments maybe envisaged, for example with a threaded contact for one polarity and aslider contact for another polarity other geometries, etc. Inembodiments of the kind of FIGS. 22-24 and 27, where indentations andprotrusions together form an interlocking structure, the BTE componentmay comprise the protrusions and the connection element thecorresponding plurality of indentations.

In the following, the handling of a hearing device according to thesecond aspect of the invention and comprising a BTE component and anexternal receiver assembly consisting of a receiver preferentiallyembedded in a housing and mechanically and electrically attached to aconnection link which preferably comprises a plastic tubing with inlayedconducting wires is described in three exemplary situations. The fourthuse case (Component Identification) has no influence on the solutionspresented herein but is mentioned for completeness.

First Case: First Fit

Precondition:

The BTE device delivered to the hearing professional preassembled, i.e.the connection link of the external receiver assembly is fully insertedin the BTE component

Optionally the receiver housing is further attached to an ear canalfixation mean such as a custom made (open) otoplastic

Main Scenario

1. The hearing professional puts the BTE component behind the user's ear

2. The hearing professional places the receiver component (housing) intothe ear canal

3. The hearing professional adjusts the connection length by pulling outthe connection link at the BTE component, until a comfort fit isachieved

4. The hearing professional can reinsert the connection link into theBTE component, if required

5. The hearing professional applies a locking means to securely fix thelength of the connection link

Post-Condition

The BTE component with an external receiver is end-assembled accordingto the individual needs of the user

Second Case: Change of Receiver Type

Precondition

The BTE component with an external receiver of a certain type isassembled according to the use case ‘First Fit’.

Main Scenario

1. The hearing professional unlocks the locking means

2. The hearing professional pulls out the external receiver assembly

3. The hearing professional inserts a new external receiver assembly(with a receiver of a different type)

4. The hearing professional continues with the use case ‘First Fit’

Post-Condition

The BTE component with a replaced external receiver is end-assembledaccording to the individual needs of the user

Third Case: Service/Repair

Precondition

The BTE component with an external receiver is assembled according tothe use case ‘First Fit’

The receiver or the connection link is damaged such that the externalreceiver assembly needs to be replaced

Main Scenario

1. The hearing professional unlocks the locking means

2. The hearing professional pulls out the external receiver assembly

3. The hearing professional inserts a new external receiver assembly(with a receiver of the same type)

4. The hearing professional continues with the use case ‘First Fit’

Post-Condition

The BTE component with a replaced external receiver is end-assembledaccording to the individual needs of the user

Fourth Case: Component Identification

Precondition

The BTE component device delivered to the hearing professionalpreassembled, i.e. the connection link of the external receiver assemblyis fully inserted in the BTE component

Or, the BTE component with an external receiver is assembled accordingto the use case ‘First Fit’

Or, the external receiver assembly has been replaced with the same ordifferent type of receiver

Optionally, the external receiver component is equipped with anidentification module as described in WO 9909799

Main Scenario

1. If automatic identification is possible, the hearing device checksduring booting the components according to WO 9909799

2. Or the hearing professional enters manually the receiver type orchanges the default value

3. The programming software causes to change and store thesettings/operations in the memory of the hearing instrument

Post-Condition

The BTE component with an external receiver is end-assembled and theconfiguration is stored in the memory of the hearing device

Now, embodiments of the of the invention are described.

The hearing instrument of FIG. 28 comprises a BTE component 301 and anin-the-ear-canal component 302. Between the BTE component and thein-the-ear-canal component a connection element 303 is arranged. Theconnection element may optionally be built according to the secondaspect of the invention. It comprises an electrical connection betweensound processing means (not shown) in the BTE component and a receiver304 arranged in the in-the-ear-canal component. It may—in accordancewith an embodiment of the first aspect of the invention—further comprisesound conduction means for conducting sound produced by a furtherreceiver being arranged in the BTE component. The BTE component mayfurther comprise hook means or the like (not shown) for hooking itbehind a user's ear.

The hearing instrument further comprises a fixation means 311 which inthe figure is pictured as a tubular element for being introduced in theear canal. The fixation means is operable to be positioned in the user'sear canal and to rest fixed therein. To this end, it is for exampleshaped to fit in the user's ear canal or it comprises—this is thepreferred set-up—a self-expandable component that may establish itselfin the ear canal. The fixation means 311 and the in-the-ear-canalcomponent 302 are operable to be reversibly mechanically connected toeach other.

In the shown embodiment, the fixation means preferably isself-expandable and has an outer diameter that is—when the fixationmeans is in an equilibrium position outside the ear—somewhat larger thanan inner diameter of the ear canal. The inside of the tubular fixationmeans is—at least when the fixation means is inserted in the user's earcanal and in its designated position—operable to hold the insertedin-the-ear-canal component 302 in position.

In accordance with the third aspect of the invention, the fixation meansis inserted in the ear canal without the in-the-ear-canal component by ahearing professional or by somebody else including the user himself.Then, the in-the-ear-canal component is inserted in the canal so thatthe sound bore 305 faces the tympanic membrane and connected to thefixation means.

The hearing instrument system realised by the hearing instrumentaccording to FIG. 28 or the following figures illustrating embodimentsof the third aspect of the invention may be as illustrated in FIG. 13,the description of which is, for reasons of conciseness, not repeatedhere. As an alternative, the hearing instrument system may comprisemultiple receivers and for example be realized in accordance with FIG. 4(or as in FIG. 4 but with woofer and tweeter exchanged).

Departing from FIG. 28, the hearing instrument system may be anin-the-canal or a completely-in-the-canal system where all constituents(except, of course, the fixation means) of the hearing instrument arearranged in the in-the-ear-canal component. The fixation system inaccordance with the third aspect of the invention further is suited forfixing any other (non-hearing-aid) devices in the ear canal, for examplereceivers belonging to a radio system.

In a first embodiment illustrated in FIG. 29 the fixation means 321 is ahollow reversibly compressible tubular element, for example made ofcompressible foam. The tube has a length of for example about 15 to 20mm and is made of biocompatible material. This tube is placed in the earcanal before the receiver component is inserted. The inner radius of thetube is such that when the tube is placed in the bony part of the earcanal, the largest cross-section is smaller than the cross section ofthe receiver component to be inserted.

The receiver component has for example an oval shape and a cross-sectionthat is minimized with regard to the cross-section of the ear canal,such that the amount of cerumen that is pushed into the ear canal duringinsertion is minimized. During insertion the receiver component isguided into the tube with the help of the oval shape of the componentand possibly with an increased inner radius at the lateral end of thescaffold. During insertion the walls of the scaffold are compressed,such that the pressure against the skin preferably does not exceed 0.05N/mm2 in the pressure sensitive area of the ear canal, i.e. in the bonyportion of the ear canal. Since the scaffold is longer than the receivercomponent the inner radius of the scaffold will be smaller than themaximum cross-section of the receiver component, which adds to theretention force, holding the receiver component longitudinally in place.

An example of a fixation element and an in-the-ear-canal componentaccording to the second embodiment of the third aspect of the inventionis shown in FIG. 30. The second embodiment is especially suited forplacing the receiver deeply in the ear canal with minimum interferencewith the physiological environment. Since the microphone may be placedfar from the receiver, it is possible to offer a non-occluding fixationof the receiver. As in the first embodiment, the assembly comprises twoconstituents placed in the ear canal. One constituent is the fixationmeans designed for long-term wear and serves as a scaffold to hold thereceiver part in place, and the other constituent is thein-the-ear-canal component comprising the receiver itself which can beinserted and removed.

The fixation means comprises a tubular element, namely a self-expandingear-canal stent 331, e.g. made of a mesh and is placed beyond the earcanal's isthmus. It is designed such that the pressure against the skinis minimized. A total length of between 10 mm and 20 mm is sufficient toproduce enough retention force. The mesh structure allows maximumcontact between the skin and the air which minimizes the physiologicalinterferences.

The inner part of the stent 331 possesses holding elements 332 (‘hairs’)that are attached at the stent wall and point radially inward (FIG. 2).The hairs are highly flexible and bend easily.

The in-the-ear-canal component 302 contains only the receiver 304 in anoval housing as for the first embodiment. The oval shaped is designedsuch that it comprises a minimum overall volume. A thin cable 303connects the receiver assembly to the BTE component. The receivercomponent is inserted using a gauge tool that guarantees the exactinsertion depths. When inserted, the receiver component is for examplelocated in the center of the ear-canal stent 331, held by the holdingelements 332 that were bent during the insertion process. The insertiononly minimally adds more pressure the stent walls and therefore to theskin. Hairs at the tube entrance and end are, after insertion of thereceiver, in their original position and hold the receiver componentlongitudinally in place. The receiver component can be inserted andremoved many times without irritating the skin.

In preferred realisations of the second embodiment, the holding elementsare configured so as to provide an enforced resistance againstlongitudinal displacement while the radial pressure on the skin is keptminimal. In a first variant, shown in FIG. 31, holding elements 332.1 ator near the tube entrance (i.e. holding elements that are, when thein-the-ear-canal component 302 is inserted, towards on the side of thein-the-ear-canal component 302 towards the ear canal's exit, arestronger. This will somewhat enhance the forces during introduction ofthe in-the-ear-canal component 302, but provides mechanical stabilityagainst unwanted removal of the in-the-ear-canal component 302 withoutany additional force upon the ear canal skin, while the receiver 304 isin its intended position. The holding elements at the fixation means'end may also be stronger than the holding elements in a middle region soas to provide some resistance against an introduction of thein-the-ear-canal component 302 too far in the ear canal. As analternative, also shown in FIG. 31, the fixation element comprisesstopping means 333 serving as an abutment securely preventing thein-the-ear-canal component from being inserted too deep in the earcanal. Such stopping means are especially advantageous since usually theuser herself/himself introduces the in-the-ear-canal component 302 inthe already mounted fixation means. The stopping means 333 may forexample be grid-like, where the grid lines are thin wires, or compriseat least two crossed wires across the tubular element's center.

As an alternative or in addition to the set-up of FIG. 31, the holdingelements may be such that they are especially stiff against an initialdisplacement, which is essentially in a longitudinal direction, where asa further displacement (primarily in radial direction) encounters aweaker resistance force. An example of such a non-linear dependence ofthe spring force on the displacement is shown in FIG. 32. Theforce-displacement curve has a pronounced peak at small displacementsand for larger displacements becomes approximately linear as an ordinaryspring. Such a behaviour—which may moreover be direction dependent (notshown)—is for example encountered for plate springs which are slightlybent around an axis which is at an angle (for example perpendicular) tothe deflection direction, as illustrated in FIG. 33. FIG. 33 shows anexample of a variant of a holding element 342 having such a non-linearbehaviour. “z” in the figures denotes the longitudinal introductiondirection. Due to this behaviour, the unbent holding elements provide anespecially good hold against unwanted longitudinal displacement, whereasthe bent holding elements at the place of the in-the-ear-canal componentonly exert a minimal radial force upon the stent-like tubular element.The realisation of FIGS. 32 and 33, compared to the realisation of FIG.31, is especially preferred in situations where the end position of thein-the-ear-canal component within the fixation means is not pre-defined.

In addition or as an alternative, the holding elements 352 may comprisebarb-like structures 355 which provide yet an additional resistanceagainst unwanted removal of the in-the-ear-canal component, as sketchedin FIG. 34. The barb-like structures may get caught in correspondingfeatures on the back side of the in-the-ear-canal component housing (notshown). This additional measure allows to make the spring constant ofthe holding element even weaker, so as to yet again reduce the radialpressure upon the tubular element.

An example of a tubular element 331 (without the holding elements) isshown in FIG. 35. The tubular element is self-expandable due to a meshstructure shown in more detail in FIG. 36. It may be of a kind alreadyknown from stents for medical applications and may be made of titanand/or stainless steel and/or other suitable material compositionsincluding synthetics.

In FIG. 37 a realisation of the second embodiment is shown, where theholding elements 362 are not hair-like but are springs radiallyextending from the inside of the tube.

In the following, embodiments of the fourth aspect of the invention aredescribed.

FIGS. 38 and 39 are shown in order to illustrate an advantage of thefourth aspect of the invention over the universal-fit holder solutionsaccording to the prior art. In such universal-fit holders, thepositioning of the receiver within the ear canal is not predictable andoften not satisfactorily reproducible. The effective vent size is apriori not known since it is defined by the ear canal geometry. Theresulting variations of the acoustic coupling are shown based on a modelsituation in FIGS. 38 and 39.

FIG. 38 shows the Real-Ear-to-Coupler-Difference (RECD) of a model tubewith a fixed vent diameter, which model tube is inserted in a model earcanal, as illustrated in the left panel. The RECD is the differencebetween the sound pressure level in a 2 cm3 coupler (being an idealisedear canal) used for standard measurements the closed ear canal and theactual sound pressure level in the real ear. The curves in the rightpanel show the frequency dependence of the RECD for different ventpositions lvent. As can be estimated from the figure, an uncertainty ofinsertion depth of around 1 mm would correspond to changes of RECD inthe order of 3 dB@2 kHz.

FIG. 39 shows the corresponding situation when the vent diameter dventis varied at a constant vent position. An uncertainty of opening areatranslated to an uncertainty of the effective vent size of about 1 mmdue to missing information about the ear canal geometry would correspondto changes of RECD in order of 5 dB@2 kHz.

The hearing instrument of FIG. 40 comprises a BTE component 401 and anin-the-ear-canal component 402. Between the BTE component and thein-the-ear-canal component a connection element 403 is arranged. Theconnection element may optionally be built according to the secondaspect of the invention. It comprises an electrical connection betweensound processing means (not shown) in the BTE component and a receiver404 arranged in the in-the-ear-canal component. It may—in accordancewith an embodiment of the first aspect of the invention—further comprisesound conduction means for conducting sound produced by a furtherreceiver being arranged in the BTE component. The BTE component mayfurther comprise hook means or the like (not shown) for hooking itbehind a user's ear.

The hearing instrument further comprises a fixation means 410. Thefixation means is shaped to fit in the user's ear canal and to restfixed therein. The fixation means 410 and the in-the-ear-canal component402 are operable to be mechanically connected to each other. Thismechanical connection may be permanent or, preferably, may bereversible.

In preferred embodiments, the fixation means is shaped to fit in anouter portion of the ear canal, i.e. outwards of the isthmus. In mostembodiments, the in-the-ear-canal component 402 is mechanicallyconnected to the fixation means outside of the ear canal and inserted inthe ear canal together with the fixation means.

The hearing instrument system realised by the hearing instrumentaccording to FIG. 40 or the following figures illustrating embodimentsof the third aspect of the invention may be as illustrated in FIG. 13,the description of which is, for reasons of conciseness, not repeatedhere. As an alternative, the hearing instrument system may comprisemultiple receivers and for example be realised in accordance with FIG. 4(or as in FIG. 4 but with woofer and tweeter exchanged).

Departing from FIG. 40, the hearing instrument system may be anin-the-canal or a completely-in-the-canal system where all constituents(except, of course, the fixation means) of the hearing instrument arearranged in the in-the-ear-canal component.

An example of the fixation means 400 is shown in more detail in FIG. 41.FIG. 41 depicts a front view (left upper panel), a side view includingan in-the-ear-canal component (right upper panel), and a top view (lowerpanel) of a fixation means in each case in section. The fixation meanscomprises an outer shell 421 which is shaped to fit in the user's earcanal. Affixed to the outer shell by means of a support structure 423 isan inner shell 422 which is formed to receive and hold thein-the-ear-canal component 402. For example, the inner shell isresilient (in fact, it may be made of the same material as the outershell) and has an inner diameter that is slightly smaller than an outerdiameter of the in-the-ear-canal component 402. The fixation meansfurther comprising a locking mechanism locking the in-the-ear-canalcomponent once it has been fully introduced into the inner shell. Thelocking mechanism in the shown example comprises a cantilever 424 with alocking protrusion 425. When the in-the-ear-canal component 402 isintroduced in the inner shell, the cantilever is swivelled outward in aradial direction, until the locking protrusion 425 snaps in acorresponding locking indentation 426 of the in-the-ear-canal component.

The shell is preferably made of polyamide. In order to achieve optimizedfit of the shell within the user's outer ear and ear canal, the shellpreferably has an outer surface individually shaped according to themeasured shape of the user's outer ear and ear canal, i.e. the shellpreferably has an individually customized outer shape. The shape of theuser's outer ear and ear canal may be determined by directthree-dimensional scanning of the ear canal and the concha or byproducing an impression of the ear canal and the concha whichsubsequently undergoes scanning. The scanning process may be carried outoptically, preferably by laser scanning.

The digital data obtained by the scanning process is then used to createthe hard shell by an additive or incremental layer-by-layer build upprocess. Such processes are also known as “rapid prototyping”. Apreferred additive build-up process is a layer-by-layer laser sinteringprocess of powder material, preferably polyamide powder. Such processesare also known as “selective laser sintering” (SLS). The basic principletherein is the repeated deposition of a thin layer of material on asurface, with the desired sectional shape then being stabilized, i.e.hardened, by laser action. Other preferred additive layer-by-layerbuild-up processes are laser stereo-lithography or photo-polymerization.An overview regarding additive layer-by-layer build-up processes forproducing customized shells for hearing aids can be found, for example,in US 2003/013358 A1 or US 6,533,062 B1.

Between the outer shell 421 and the inner shell 422 a passage 429remains open. In the shown embodiment, the cross section of the passageis larger than the cross section of the inner shell with thein-the-ear-canal component.

The length in a longitudinal direction, i.e., a direction correspondingto the ear canal axis, of the outer shell and of the inner shell isapproximately equal to the longitudinal length of the in-the-ear-canalcomponent.

The in-the-ear-canal component 402 for example comprises a housing witha universal shape (i.e., the shape is independent of the individual'sear and the same for all users) and comprises a shape which allowsmounting of the in-the-ear-canal component to different kinds offixation means.

Even though the fixation mean is shaped to the individual ear geometry,it is possible to use the actual and real vent dimensions (dimension ofthe passage) for optimizing the acoustic coupling during the fittingprocess. This is because the manufacturing is of the fixation mean isbased on digitized data and both vent size and insertion depth arecontrolled parameters.

The outer shell may be formed by an outer shell wall that is continuousor that comprises wall openings 431 as is illustrated in FIG. 42. Theouter shell may as an alternative comprise an otherwise open structure,such as a mesh structure. An structure with wall openings or anotherwise open structure has the aim to reduce the amount of material toa minimum while still imaging the individual ear canal geometry, tofavour the resilient behaviour and at the same time to support minimalinterference with the skin physiology.

Alternative embodiments of the fixation means are shown in front view inFIG. 43. The inner shells 442, 452 of the variants A and B are arrangedasymmetrically near a wall of the ear canal. In variant A, the wall ofthe inner shell in a section coincides with the wall 441 of the outershell, whereas in variant B a support structure 453 is arranged betweenthe inner shell 452 and the outer shell 451 and provides an additionalmechanical de-coupling between the canal wall and the in-the-ear-canalcomponent. This may be advantageous for situations where thein-the-ear-canal component noticeably vibrates when low frequency soundsare produced be the receiver. The mechanical de-coupling prevents thevibrations from being transferred to the canal wall where they may causea tickling sensation. In variant C, the inner shell 462 is locatedcentrally within the outer shell 461 and is held by a suspensionstructure 463 that comprises holding elements that extend essentiallyradially from the inner shell to the outer shell but that are shaped soas to not exert too strong a spring force against deformations of theouter shell (i.e. they may for example be sheet like and bended asillustrated in the figure).

The outer shell and the mounting structure (in all so far describedembodiments, the mounting structure comprises an inner shell), thoughsuch a design is preferred, both need not be circumferential, i.e. neednot, in at least one section, form a closed shape surrounding the earcanal on an interior or the in-the-ear-canal component on an exteriorside, respectively. An example of an embodiment where the outer shell471 is not circumferential is shown in FIG. 44. The outer shell in anupper portion is completely open. The elasticity of the outer shellmaterial and the spring force of the holding elements of the supportstructure 473 nevertheless causes the outer shell to rest against thecanal wall once the fixation means is inserted. In the embodiment ofFIG. 45, the outer shell 481 is circumferential, but the mountingstructure comprises an inner shell 482 that is made of two inner shellproportions for framing the in-the-ear-canal component from two sides(in the figure from an upper and a lower side). In both, FIG. 44 andFIG. 45, the inner shell 472, 482 is held centrally in the ear canal bythe support structure 473, 483.

In FIG. 46, a locking mechanism for locking the in-the-ear-canalcomponent 502 in the inner shell 492 is illustrated in more detail. Thelocking mechanism may be a snap-in-twist-off mechanism where thein-the-ear-canal component may be removed by being twisted relative tothe fixation means. Apart from the locking mechanism—which may beprovided by a cantilever-like spring 494—the locking mechanism does notrequire any additional tools.

1. A hearing instrument comprising at least one microphone, at least onesignal processing unit and at least one receiver and comprising abehind-the-ear component which fits behind a user's ear and contains atleast the signal processing unit, and an external component adapted tobe placed in the user's ear or in the user's ear canal and whichcomprises at least one of said at least one receivers, and a connectionlink between the behind-the-ear component and the external component,the connection link comprising at least two electrical contact lines,the connection link being reversibly connectable to the behind-the-earcomponent and/or the external component, the connection link having alength that is reversibly adjustable, and the hearing instrumentcomprising fixation means for reversibly fixing the adjusted length ofthe connection link.
 2. A hearing instrument according to claim 1,wherein the behind-the-ear component or the external component comprisesa cavity, and wherein the connection link comprises a connection elementthat is partially insertable into said cavity to varying extents, sothat the connection link's length is adjustable.
 3. A hearing instrumentaccording to claim 2, wherein the external component is anin-the-ear-canal component adapted to be placed in the user's ear canaland comprising fixation means for fixing it therein, wherein the cavityis formed in the behind-the-ear component, and wherein the connectionlink is reversibly connectable to the external component.
 4. A hearinginstrument according to claim 2, wherein the behind-the-ear componentcomprises a hook for hooking the behind-the-ear component behind auser's ear, and wherein the cavity is formed in the hook.
 5. A hearinginstrument according to claim 1, wherein a connection element formingthe connection link has one end with an elongated shape defining alongitudinal direction and at least two first electrical contacts whichco-operate with corresponding second electrical contacts of thebehind-the-ear component or the external component, wherein at least oneof the first electrical contacts and of the second electrical contactsis extended over range of positions or a plurality of positions in thelongitudinal direction so that an electrical contact between the firstand second electrical contacts is formable in a range or a plurality ofrelative longitudinal positions of the first and second electricalcontacts, and wherein the fixation means are operable to fix therelative longitudinal positions of the first and second electricalcontacts.
 6. A hearing instrument according to claim 5, wherein thefirst and second electrical contacts together form slider contacts.
 7. Ahearing instrument according to claim 6, wherein the first or the secondelectrical contacts are spring contacts producing a contact forcebetween the first and the second electrical contacts.
 8. A hearinginstrument according to claim 6, wherein the fixation means comprise athreaded sleeve attached to the connection element or a threaded portionof the connection element, co-operating with a corresponding insidethreaded counterpart of the behind-the-ear component or the externalcomponent, and wherein the at least two first electrical contacts or theat least two second electrical contacts or the at least two firstelectrical contacts and the at least two second electrical contactscomprise a cylindrical portion.
 9. A hearing instrument according toclaim 5, wherein the first and the second electrical contacts arethreaded.
 10. A hearing instrument according to claim 5, wherein thefirst or the second electrical contacts comprise at least one protrusionand wherein the second or the first electrical contacts, respectively,comprise a plurality of corresponding indentations.
 11. A hearinginstrument according to claim 1, wherein the fixation means comprise aset screw and wherein the connection link comprises a connection elementwith a section that is at least partially plastically deformable, andwherein the set screw is pressable into the at least partiallyplastically deformable section, whereby fixation is achieved.
 12. Ahearing instrument according to according to claim 1, wherein thefixation means comprise radially extending protrusions or radialindentations of the connection element co-operating with inversestructures of the behind-the-ear component or the external component,respectively.
 13. A hearing instrument according to claim 5, wherein thefixation means comprise a set screw and wherein the connection linkcomprises a connection element with a section that is at least partiallyplastically deformable, and wherein the set screw is pressable into theat least partially plastically deformable section, whereby fixation isachieved.
 14. A hearing instrument according to according to claim 5,wherein the fixation means comprise radially extending protrusions orradial indentations of the connection element co-operating with inversestructures of the behind-the-ear component or the external component,respectively.
 15. A hearing instrument according to claim 1, wherein theexternal component is an in-the-ear-canal component adapted to be placedin a user's ear canal, the hearing instrument comprising a fixationmeans adapted to fit in the user's ear canal and to be fixed therein,wherein the in-the-ear-canal component is reversibly connectable to thefixation means when the fixation means are positioned in the ear canaland reversibly detachable from the fixation means when the fixationmeans are positioned in the ear canal.
 16. A hearing instrumentaccording to claim 1, wherein the external component is anin-the-ear-canal component adapted to be placed in a user's ear canal,the hearing instrument comprising a fixation means for fixing thein-the-ear canal component in a user's ear, the fixation meanscomprising an outer shell shaped to fit in the user's ear canal and anin-the-ear-canal component mounting structure mechanically coupled tothe outer shell and being shaped to hold the in-the-ear-canal component,wherein the in-the-ear-canal component is reversibly mountable to thefixation means, and wherein the fixation means is shaped so as tomaintain a passage from an outside to an interior of the ear canal whenthe in-the-ear-canal component is inserted.
 17. A method of adapting ahearing instrument to a user's anatomy, the hearing instrumentcomprising a behind-the-ear component and an external component forbeing placed in the user's ear or in the user's ear canal and whichcomprises at least one receiver, and a connection link between thebehind-the-ear component and the in-the-ear-canal component, theconnection link comprising at least two electrical contact lines, theconnection link being reversibly connectable to the behind-the-earcomponent or the external component, the method comprising the steps ofplacing the behind-the-ear-component behind the user's ear, of placingthe external component in the user's ear canal or the user's ear, ofadjusting the length of the connection link until a comfort fit isachieved, and of applying a locking means to fix the length of theconnection link.
 18. A method of fixing an in-the-ear-canal component ofa hearing instrument in a user's ear canal comprising the steps ofproviding a fixation means adapted to fit in the user's ear canal and tobe fixed therein, of placing said fixation means in the user's earcanal, and of connecting the in-the-ear-canal component to the fixationmeans placed in the ear canal.
 19. A method according to claim 18,wherein the fixation means is placed beyond the ear canal's isthmus. 20.A method according to claim 19, wherein the fixation means comprises acompressible tube, the outer diameter of which, if it is in ade-compressed state, is larger than the outer diameter of the user's earcanal, and wherein the method comprises the steps of, before introducingthe fixation element in the ear canal, applying a compression force onsaid tube, and of, after placing said tube in the user's ear canal,releasing said compression force.
 21. A method according to claim 20,wherein the step of connecting the in-the-ear-canal component to thefixation means placed in the ear canal includes introducing thein-the-ear-canal component into an interior of said compressible tube.